More than 1,000 miles of unpaved roads in Pinal County create air-quality problems when dry and accessibility problems for school buses, public safety and motorists when wet.
But the solution to those problems - paving - is hampered by funding limitations and lack of access to segments of dirt roads that are privately owned.
Over the last year, the county paved about 70 miles of road and had about 27 miles annexed into cities or towns. That left about 1,100 miles of unpaved or gravel roads, compared with 986 miles of paved road.
"It's an inescapable truth - paved roads generate less dust than unpaved roads," Pinal County air quality director Don Gabrielson said. "But the volume of road dust generated is a function of the amount of traffic and nature of the traffic."
But there isn't a cut-and-dried solution to the dust problem, he said. The county currently monitors for dust and is meeting with county stakeholders to study and develop regulations related to particulate matter in the air, he said.
It's easy to say pave all the roads, but that addresses only one contributor to the dust problem, Gabrielson said. Agricultural land, for example, also contributes, he said.
"It is a communitywide issue, and it needs to be a communitywide response. It's not a matter of singling out a particular culprit. It's important for Pinal County to have that discussion and come to grips with the issue on its own."
Pinal County Supervisor Sandie Smith said the county has chip-sealed some roads to help keep dust down. Chip-sealing involves using a bonding agent to control dust and improve the surface of unpaved roads.
Gene Nemeth, who lives in the San Tan area, said the chip-sealing helped with dust in the area, even though it isn't the best surface to drive on when it rains. He said the dust used to be terrible, and he suspects that it could have affected home sales.
"When I first moved there in 1974, they were just mud, dirt trails," he said. "The chip seal really did help with the dust over the years."
Florence Unified School District transportation assistant Shannon Arterbury said the district finds challenges with rain-soaked dirt roads, and the wear and tear even dry dirt roads cause, on buses.
"When the dirt roads get wet from consistent rain, we can't get in there with the buses and have to make changes to the bus stop locations," she said. "Our parents know in the event of consistent rain, there's an alternative location, but it throws a hitch in everyone's schedule."
Unpaved roads also affect access by public safety vehicles.
"Our deputies have been dealing with unpaved roads forever," said Vanessa White, spokeswoman for the Pinal County Sheriff's Office.
Unpaved roads generally have lower speed limits, and if the roads aren't well-maintained, that slows down deputies as well, she said.
"It will hinder response times," she said. "But as the county is growing, more roads are paved, and that is going to only help response times."
Pinal County officials said they face funding constraints for paving, but they also face having to determine whether to pave more roads or widen the paved roads they already have.
"It's evolving from agricultural to more developed land," public works director Greg Stanley said. "We don't have enough money to pave the roads and at the same time deal with congestion issues. We have to look at what to pave versus how to deal with congestion."
Stanley said the county's half-cent sales tax goes to funding road construction and improvements, and a majority of that money is spent turning gravel roads to pavement.